PayPal Website Payments Pro payments module cannot verify login credentials

I am using the osCommerce PayPal Website Payments Pro (UK) Direct Payments payment addon but cannot enable the module as it gives the following error:

Error: Payment module conf开发者_Go百科iguration error. Please verify the login credentials.

I've entered my client's ID in the vendor section and their password, but still cannot work out why it won't work.

Check that you have entered the correct PayPal certification keys and client IDs. If you have access to his PayPal account, look to create a certificate (the info is helpful) and test it in sandbox first.

The osCommerce PayPal module has a bug that doesn't correctly send the products ordered to PayPal. This happens mostly in the PayPal Express Checkout module.

This is what is needed exactly from PayPal (from your live PayPal account):

• API Username
• API Password
• API Signature

If you need to run test transactions, sign-up/log into the PayPal Sandbox.

You will need generate Buyer and Seller accounts in the Sandbox and configure the API Username, API Password and API Signature information into osCommerce instead of using the API credentials from your live account.